Cannot run qtdemo - directory missing

[fopetesl]

qtdemo should get compiled when you compile Qt itself. qt_x11_p.h is part of Qt4 source tree.

Thanks wysota. My package is/was part of the Mandriva library so I (mistakenly) assumed it is/was complete.
Since I appear to be running 4.1.4 can I either just download the missing part(s) from where
or, if up download the 4.2.x package am I likely to break anything in recompiling?
I already seem to have 3.x installed though why I don't know - can I remove this with impunity?